The types of products to which the present invention relates include baked goods that are baked from dough pieces having an outer layer of farinaceous dough and a core which may be a dissimilar dough or another material such as a jam, cream, puree, paste, or other extrudable form of fruit, cheese, meat, vegetable, confection or other edible substance. In those products where the core is also a dough, the inner and outer doughs would be advantageously dissimilar in composition so as to produce different tastes, colors, appearances, textures, consistencies, or the like in the inner and outer portions of the baked product. Regardless of the composition of the inner and outer portions, the present invention is directed to products having particulate matter, such as chocolate chips, candied fruit, nuts, raisins, and the like, in the outer portion.
In the past, products having different inner and outer portions have been formed by concentrically extruding an extrudate rope as shown in U.S. Pat. No. 3,572,259 to Hayashi.
An automatic machine for making filled baked goods is described in U.S. Pat. No. 3,196,810 to Roth. In this patent, a plurality of dies dispose flavoring material within a dough. U.S. Pat. No. 3,778,209 to Wallace et al. discloses an apparatus for forming a food extrusion in which an inner meat food is totally enrobed by an outer moldable food by using a co-extrusion nozzle and a pair of augers to force food products through the co-extrusion nozzle from a respective pair of food hoppers. Augers are particularly useful for the extrusion of foods, such as dough, in order to achieve a consistent quality, reliability and high efficiency in the high speed manufacture of snacks such as cookies, chocolate layered foods and the like.
In the manufacture of co-extruded food substances, it is common to require that the outer food substance encapsulates or enrobes an inner food substance. In U.S. Pat. No. 3,778,209 to Wallace et al. and U.S. Pat. No. 3,249,068 to Gembicki, the enrobing action is obtained by controlling the motion of a plunger or piston used in connection with the feeding of the food material to be encapsulated. In U.S. Pat. No. 4,251,201 to Krysiak, an enrobed food piece is produced with an apparatus that includes specially sequenced feed mechanisms used to co-extrude an inner and outer food product from coaxial dies in combination with a sequence coordinated iris shaped cut-off valve that is closely mounted to the discharge ports of the extrusion dies. The iris valve cuts the co-extrusion just at a time when the feed of both the inner filler and outer enrobing foods is interrupted and the space in which the valve acts is essentially filled with the outer enrobing food. This technique appears to depend upon a relatively easy flowability of the outer food substance so as to coat the rear of the inner food while the iris valve is about to close and appears limited in operating speed because the feed of both inner and outer foods must be interrupted for each food piece manufactured.
More recently, relatively high speed methods and apparatuses have been developed whereby an inner dough co-extruded with an outer dough is enrobed by severing the outer dough with a blunt severing edge or a severing element which simultaneously draws the outer dough over the inner dough on both sides of a severed element to form a fully enrobed food piece. See, for example, commonly-assigned U.S. patent application Ser. No. 06/507,401.
In all the known methods discussed above, there is no disclosure of including particulate matter in the outer dough portion. Consequently, none of the references disclose any method or apparatus which facilitates inclusion of particulate matter in the outer portion of a co-extruded dough rope.
Experience in the art of co-extrusion has taught that certain difficulties are encountered in extruding an outer tube of doughy mass containing particulate matter. For example, the normal configuration of the die head is such that the annular space between the outside circumference of the inner extrusion port and the inside of the outer extrusion port prevents smooth passage of the particulate matter. In some cases, the space when adjusted to provide the proper flow rate and tube thickness is simply too small to allow passage of the particles. Another problem encountered is the agglomeration of particles is they enter the exit passage which blocks the flow of extrusion or causes an uneven outer tube of dough.
When it is desired to extrude a particle-containing outer of dough mass to produce an attractive relatively smooth-skinned confectionery or cookie having the particulate matter appear as if placed thereon externally or prepared by hand, the problems are intensified. The particles are desirably free from a partial covering by the doughy mass. This enhances the appearance of the finished product which is an important commercial consideration. In order to enhance the product's appearance, the particles should penetrate the exterior surface of the outer dough and should be free of a partial covering by the doughy mass.
A further consideration relative to extruding the outer tube of doughy mass with particles is that the integrity of the outer dough portion should be maintained, especially in the case of co-extruded cookie dough, so that the final product appears wholly handmade. Any discontinuities through which the inner portion can be seen significantly erodes the appearance of a handmade quality for the product.
Moreover, it would be desirable that each of the above considerations be resolved while maintaining high speed production.